newlib-cygwin/newlib/libc/stdlib/strtol.c

227 lines
7.5 KiB
C
Raw Normal View History

2000-02-18 03:39:52 +08:00
/*
FUNCTION
<<strtol>>---string to long
INDEX
strtol
INDEX
_strtol_r
ANSI_SYNOPSIS
#include <stdlib.h>
long strtol(const char *<[s]>, char **<[ptr]>,int <[base]>);
long _strtol_r(void *<[reent]>,
const char *<[s]>, char **<[ptr]>,int <[base]>);
TRAD_SYNOPSIS
#include <stdlib.h>
long strtol (<[s]>, <[ptr]>, <[base]>)
char *<[s]>;
char **<[ptr]>;
int <[base]>;
long _strtol_r (<[reent]>, <[s]>, <[ptr]>, <[base]>)
char *<[reent]>;
char *<[s]>;
char **<[ptr]>;
int <[base]>;
DESCRIPTION
The function <<strtol>> converts the string <<*<[s]>>> to
a <<long>>. First, it breaks down the string into three parts:
leading whitespace, which is ignored; a subject string consisting
of characters resembling an integer in the radix specified by <[base]>;
and a trailing portion consisting of zero or more unparseable characters,
and always including the terminating null character. Then, it attempts
to convert the subject string into a <<long>> and returns the
result.
If the value of <[base]> is 0, the subject string is expected to look
like a normal C integer constant: an optional sign, a possible `<<0x>>'
indicating a hexadecimal base, and a number. If <[base]> is between
2 and 36, the expected form of the subject is a sequence of letters
and digits representing an integer in the radix specified by <[base]>,
with an optional plus or minus sign. The letters <<a>>--<<z>> (or,
equivalently, <<A>>--<<Z>>) are used to signify values from 10 to 35;
only letters whose ascribed values are less than <[base]> are
permitted. If <[base]> is 16, a leading <<0x>> is permitted.
The subject sequence is the longest initial sequence of the input
string that has the expected form, starting with the first
non-whitespace character. If the string is empty or consists entirely
of whitespace, or if the first non-whitespace character is not a
permissible letter or digit, the subject string is empty.
If the subject string is acceptable, and the value of <[base]> is zero,
<<strtol>> attempts to determine the radix from the input string. A
string with a leading <<0x>> is treated as a hexadecimal value; a string with
a leading 0 and no <<x>> is treated as octal; all other strings are
treated as decimal. If <[base]> is between 2 and 36, it is used as the
conversion radix, as described above. If the subject string begins with
a minus sign, the value is negated. Finally, a pointer to the first
character past the converted subject string is stored in <[ptr]>, if
<[ptr]> is not <<NULL>>.
If the subject string is empty (or not in acceptable form), no conversion
is performed and the value of <[s]> is stored in <[ptr]> (if <[ptr]> is
not <<NULL>>).
The alternate function <<_strtol_r>> is a reentrant version. The
extra argument <[reent]> is a pointer to a reentrancy structure.
RETURNS
<<strtol>> returns the converted value, if any. If no conversion was
made, 0 is returned.
<<strtol>> returns <<LONG_MAX>> or <<LONG_MIN>> if the magnitude of
the converted value is too large, and sets <<errno>> to <<ERANGE>>.
PORTABILITY
<<strtol>> is ANSI.
No supporting OS subroutines are required.
*/
/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <_ansi.h>
#include <limits.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <reent.h>
/*
* Convert a string to a long integer.
*
* Ignores `locale' stuff. Assumes that the upper and lower case
* alphabets and digits are each contiguous.
*/
long
_DEFUN (_strtol_r, (rptr, nptr, endptr, base),
struct _reent *rptr _AND
_CONST char *nptr _AND
char **endptr _AND
int base)
{
register const char *s = nptr;
register unsigned long acc;
register int c;
register unsigned long cutoff;
register int neg = 0, any, cutlim;
/*
* Skip white space and pick up leading +/- sign if any.
* If base is 0, allow 0x for hex and 0 for octal, else
* assume decimal; if base is already 16, allow 0x.
*/
do {
c = *s++;
} while (isspace(c));
if (c == '-') {
neg = 1;
c = *s++;
} else if (c == '+')
c = *s++;
if ((base == 0 || base == 16) &&
c == '0' && (*s == 'x' || *s == 'X')) {
c = s[1];
s += 2;
base = 16;
}
if (base == 0)
base = c == '0' ? 8 : 10;
/*
* Compute the cutoff value between legal numbers and illegal
* numbers. That is the largest legal value, divided by the
* base. An input number that is greater than this value, if
* followed by a legal input character, is too big. One that
* is equal to this value may be valid or not; the limit
* between valid and invalid numbers is then based on the last
* digit. For instance, if the range for longs is
* [-2147483648..2147483647] and the input base is 10,
* cutoff will be set to 214748364 and cutlim to either
* 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
* a value > 214748364, or equal but the next digit is > 7 (or 8),
* the number is too big, and we will return a range error.
*
* Set any if any `digits' consumed; make it negative to indicate
* overflow.
*/
cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
cutlim = cutoff % (unsigned long)base;
cutoff /= (unsigned long)base;
for (acc = 0, any = 0;; c = *s++) {
if (isdigit(c))
c -= '0';
else if (isalpha(c))
c -= isupper(c) ? 'A' - 10 : 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
2000-02-18 03:39:52 +08:00
any = -1;
else {
any = 1;
acc *= base;
acc += c;
}
}
if (any < 0) {
acc = neg ? LONG_MIN : LONG_MAX;
rptr->_errno = ERANGE;
} else if (neg)
acc = -acc;
if (endptr != 0)
*endptr = (char *) (any ? s - 1 : nptr);
return (acc);
}
#ifndef _REENT_ONLY
long
_DEFUN (strtol, (s, ptr, base),
_CONST char *s _AND
char **ptr _AND
int base)
{
return _strtol_r (_REENT, s, ptr, base);
}
#endif